“It’ll get better with age,” Thom Yorke said, a tongue-in-cheek semi-apology after Radiohead had debuted the song “Full Stop” before a full house at the First Midwest Bank Amphitheatre in Tinley Park, Ill.

Radiohead is one of the more revered bands of the last two decades because they rarely do the expected, and they make a habit of taking chances. They sweat over songs in the studio, then let them marinate, finding their true identity in performance. And so it was Sunday with a batch of tracks from their last two albums, “In Rainbows” (2007) and “The King of Limbs” (2011), as well as newly written songs “Full Stop” and “Identikit.”

The U.K. quintet has gone from a straight-ahead rock combo, loosely associated with the Brit-pop movement of the mid-‘90s, to one that works the boundary between rock and electronic music, melody and noise, pop and the avant-garde. In recent years, the music has acquired a new looseness and swing, putting a syncopation in the step of many new songs and transforming Yorke into a dancing dervish.

The rhythm oil was flowing from the start with two drummers – full-timer Phil Selway joined by tour accomplice Clive Deamer – and Jonny Greenwood and then Ed O’Brien adding percussion. The giddy-up drum fills that sent “There There” spiraling, the twitchy “15 Steps,” the way the drum break split open “Morning Mr. Magpie” – melody often took a back seat to rhythm, and the liberation was felt as well as seen in Yorke’s king-of-limbs flurry of knees, elbows and hips.

With bassist Colin Greenwood sandwiched between Selway and Deamer, Radiohead flirted with beats that had more in common with dubstep, reggae and electro-funk than the heavier, steadier rhythms of rock. Drum sticks scurried, and at times the groove suggested the abstract funk of Miles Davis’ “Bitches Brew” and Herbie Hancock’s “Sextant.”

All of which has made for a tough decade for Radiohead fans raised on song-oriented ‘90s albums “The Bends” and “OK Computer,” which were skimmed slightly in Sunday’s set. Most of the material came from the band’s “Kid A”-and-beyond era, where texture and rhythm have dominated. Where are the songs? some might complain. But they’re still hanging around, just not as obvious as before.

The stately piano ballad “Codex” stood out as a dramatic change of pace, a reminder that nobody mourns quite like Yorke. “Karma Police” wrapped a threat inside a bittersweet hymn. A snippet of R.E.M.’s “The One I Love” ushered in “Everything in its Right Place.” But they were the exceptions on a night when the band embraced the physical as much as the cerebral, favoring movement over melancholy. There was the spastic “Lotus Flower,” and the aggression bordering on uncharacteristic macho swagger that gripped “Myxomatosis.” Yorke played air drums during “Little by Little” and even O’Brien was bouncing around the stage during the furious “Idioteque.”

“Full Stop” clipped along like it was trying to race ahead of its competition, while Jonny Greenwood draped ghostly keyboard sounds over the top. “Bodysnatchers” turned three guitars into one big percussive assault, and when Deamer joined Selway on drums about halfway through, the effect was staggering.

“I have no idea who I am anymore,” an affable Yorke cracked during the jokey band introductions. But Radiohead wouldn’t have it any other way. As Sunday reaffirmed, they hate standing still.